Embedded Body Style breaks Fusion Style

We are trying to have a node where the body is an email (html email).

However for most emails, they have a <style> section which breaks the whole style of the site. The <style> seems to replace the fusion style definition. i.e., if there is a black background, instead of having only a black background for the node body, you will get a black background for the entire page instead of the Fusion standard background.

This seems a pretty basic issue but impossible to find references on the Web

Any help really appreciated